Beyond the ancient town walls, follow the Kultuurikilomeeter through the picturesque Kalamaja neighbourhood to find Soviet-era monoliths, unconventional museums and stylish eateries.

If you know anything about the Estonian capital Tallinn, it is likely to be the chocolate-box appeal of its medieval Old Town, a Unesco-protected jumble of intertwining alleys and picturesque courtyards. Most visitors see little more than this cobblestoned labyrinth, happily taking in red-rooftop views from medieval turrets and sipping cocktails in cosy vaulted cellars.

The Old Town deservedly hogs the marketing limelight, but it is hugely rewarding to step outside of the ancient town walls and experience Tallinn's unsung treasures. The small city (population: 425,000) is a charmingly compact blend of church spires, glass skyscrapers, Baroque palaces, brooding battlements, shiny shopping malls and cafes set on sunny squares – with a few Soviet throwbacks in the mix, for added spice.

Tallinn's renaissance
Since joyfully regaining its independence in 1991, Estonia has turned its focus to the west, transforming itself into a modern, internet-savvy country (fun fact: Skype software was invented here). It is also determined to catch up with its Nordic neighbours in the quality-of-life stakes, thanks to its robust ties with nearby Finland (Helsinki is just 80km across the water, and frequent ferries connect the two cities).

Travellers may be pleasantly surprised to discover stylish restaurants plating up oh-so-fashionable New Nordic cuisine, and a design scene taking its cues from Scandinavia. There is also an ever-growing number of museums, including award-winning modern-art repository Kumu and the fascinating new KGB museum, which explains how the state security agency kept tabs on visitors during the Soviet era (they operated from a spy base atop Hotel Viru, the only hotel in Tallinn where foreigners were permitted to stay).

Picturesque neighbourhoods are ripe for exploration, and areas gaining traction with visitors include beachside Pirita and leafy, affluent Kadriorg, both east of the Old Town and easily reached by tram or bus. However, the best place for a taste of local life is Kalamaja, a district just northwest of the Old Town. Its name translates as “Fish House” and it traditionally served as the town’s main fishing harbour. It is an old quarter filled with distinctive wooden houses, and, like all good working-class neighbourhoods, is emerging as a hang-out for artists, with quirky and affordable spots to eat, drink and play.

The Culture Kilometre
The Kultuurikilomeeter (Culture Kilometre) opened in 2011 to coincide with Tallinn's turn in the spotlight as European Capital of Culture – a title it shared for the year with Turku, Finland. Despite the name, it is actually a 2km pedestrian and bike path, developed to provide easy access from the city centre and Tallinn Passenger Port (Vanasadam) to the cultural sites of Kalamaja.

Although the path is not signposted, it does appear on most tourist maps. Start by the abandoned Linnahall on the waterfront in the port area which lies just to the northeast of the Old Town. Nothing says "former Soviet" like a gigantic public building made of concrete, and the bunker-like Linnahall certainly fits the bill. Built for the 1980 Moscow Olympics (for which Tallinn hosted the sailing events) and originally christened the Lenin Palace of Culture and Sport, the Linnahall contains within its crumbling, much-graffitied hulk a vast concert hall. Concrete steps lead up to the roof – a favourite spot for young partygoers to bring drinks and watch the sunset before a night out, or watch the sunrise after a night of clubbing. It is a great place to enjoy watery Gulf of Finland views and contemplate Soviet-era Tallinn – this was the northwestern edge of the Soviet Union, after all.

Heading west, you will pass the ramshackle Museum of Contemporary Art inside a former power plant. It is a small and unconventional museum that started as an artists' squat, with free changing exhibitions showcasing often provocative video, photography and sculpture.

Opposite the museum is the KultuuriKatel (Culture Cauldron), where work is underway to transform the gasworks into Tallinn's own miniature version of London's Tate Modern gallery by 2015, combining art galleries, music studios and public spaces.

Continuing along the path, you will reach Kalasadam, the small fishing-boat harbour that gives the area its name (kala means fish, sadam means harbour)., and where the Estonian Design House is located. This showroom of locally designed clothing, textiles and accessories reveals strong Nordic influences, with ceramics and carved juniper wood used for homewares, and fabrics often adopting the patterns found in traditional Estonian folk dress. The cafe Kohvik Klaus has a funky retro-inspired interior and plump sofas on its big terrace – perfect for a breakfast of Belgian waffles or a late-night cocktail.

Next is the path's most intriguing pitstop: crumbling, eerie Patarei, built as a sea fortress under Russian tsar Nicholas I in 1840, but served as a prison from 1920 to 2005. When you see the state of decay, plus the grim, damp conditions, it is incredibly difficult to imagine that prisoners were kept here until only eight years ago. Tours are possible, but you can also snoop around on your own (the hanging room and the exercise pens paint a sombre picture, while the remnants of the medical area are unsettling). Behind the prison, at the fenced waterfront, is a drink kiosk and a bizarre strip of sand where concerts and parties are staged in summer.

The trail's final attraction is the vast and impressive Seaplane Harbour, garnering tourist and architectural plaudits since its opening in May 2012. Huge concrete hangars from the 1920s house an interactive, kid-friendly maritime museum complete with a 1936 mine-laying submarine, a British seaplane that saw active duty in World War I and a large aquarium revealing the fishy inhabitants of the Baltic Sea.

From the Seaplane Harbour, wander about 1.5km south  through the residential streets of Kalamaja  to reach the Balti jaam market behind the eponymous main train station. It offers a taste of old-school Russia, selling everything from fruit and vegetables to knock-off Lenin alarm clocks, with lots of fascinating junk shops to delve through.

About 700m west of here on the edge of Kalamaja is a favourite local haunt, the Telliskivi complex, an old warehouse cluster that is now used as a creative community hub with artist studios, workshops, band rehearsal spaces and more. If you visit, it is hard to resist the cool, casual eatery F-hoone, where industrial-chic decor meets an international menu of superbly priced dishes – such as crispy pork belly, lamb burgers or Thai tom kha soup – plus one of the country's finest creme brulees.

Cross the railway lines and walk off your meal with an amble through Schnelli Park, just a short stroll from the medieval magnificence of the Old Town.